Place egg, oil and sugar in mixing bowl. Mix well.
Add flour, baking soda, cinnamon powder and salt. Mix well.
Lastly, add in grated carrot and chopped walnut. Incorporate them well.
Line a 8 inch square pan with parchment paper with two sides hanging out.
Pour batter into baking pan. Bake at 180C, for 35-40 minutes.
Stand cake to cool for 5 minutes when done.
For cream cheese topping, beat cream cheese and butter till light and fluffy.
Pour lemon juice in and add in icing sugar slowly. Mix them well.
Spread the cream cheese mixture in between cake and on top of cake. Let it cool in fridge for about an hour before serving. Done